Originally Posted by Anno_Domini
It's pretty much in the order of this:
1.) The Dent Act went into action; Batman isn't needed.
2.) Bruce Wayne retired the cape and cowl but didn't move on because the one person he loved is dead.
3.) Bruce spent years on the energy project focusing all of his time and money but he mothballed the project after an article was released on how nuclear fusion can become a nuclear weapon; Bruce Wayne becomes a recluse for the next three years.
Agreed. Would it surprize you to know that some people think all that was due to his dead "girlfriend"?